It is known in the art relating to robotic roller hemming to pre-hem sheet metal fabricated parts, such as vehicle closure panels or other similar workpieces, to a pre-hem condition prior to the hemming of the closure panels. A vehicle closure panel may consist of an outer panel and an inner panel, which are hemmed together in a hemming process. In the hemming process, it is known to pre-hem the outer corners of a closure panel, for example by bending the corners of the outer panel towards the inner panel. Known methods for pre-hemming closure panels utilize robotic roller hemmers to hem the corners of the outer panel over the inner panel. These methods, however, require several passes with the hem roller and therefore require a significant amount of time. Further, use of a robotic roller hemmer does not always lead to a quality corner pre-hem, as the hem roller does not have the shape required to accurately make a corner pre-hem. The hem roller is therefore often ineffective for corner pre-hem operations.